1. Technical Field
The present invention relates to an electro-optical device such as a liquid crystal device and an electronic apparatus having the electro-optical device such as a liquid crystal projector.
2. Related Art
Generally, in an electro-optical device, a plurality of external circuit connection terminals are disposed along a periphery of one side of a substrate where display electrodes such as pixel electrodes and circuit units for driving the display electrodes such as a data line driver circuit and a scan line driver circuit are disposed in addition, a plurality of lead lines which are led from a plurality of the external circuit connection terminals to the circuit units such as a scan line driver circuit and a data line driver circuit are formed on the substrate. In many cases, the data line driver circuit is disposed along one side of the substrate where the external circuit connection terminals are disposed, and the scan line driver circuit is disposed along at least one side of two sides which are located at both end of the one side.
A clock signal which is a basic signal for a driving operation of the data line driver circuit and an inverted clock signal having an inverted phase with respect to the clock signal are applied from an external circuit through the external circuit connection terminals and the lead lines to the data line driver circuit. Since it is preferable that a phase of the clock signal and a phase of inverted clock signal are accurately inverted phases, a phase difference compensation circuit which compensates for the phases of the two clock signals so as to be the inverted phases is also disposed on the substrate (see JPA 2004-126551).
According to a technique disclosed in JPA 2004-126551 proposed by the inventors, in order to reduce noise of image signals originated from the clock signal and the inverted clock signal which characteristically have a very high frequency, the image signals are led from one side (for example, in proximity of the left side) of the data line, and the clock signals are led from the other side (for example, in proximity of the right side) of the data line. In addition, in order to provide a function of electromagnetically shielding the image signal lines from the clock signals which are high frequency noise sources and in order for the lead lines not to intersect each other on the substrate, low potential power supply lines for, for example, a ground potential are led from one side (for example, in proximity of the left side) of the data lines along the image signal lines to the phase difference compensation circuit, and high potential power supply lines are led from the other side (for example, in proximity of the right side) of the data lines along the clock signal lines to the phase difference compensation circuit. The clock signal, the inverted clock signal, various power supply signals, image signals, control signals, and various signals for operating the data line driver circuit and the phase difference compensation circuit can be applied through theses lines.
In addition, in order to reduce failures in operations due to interference to such signals, a research for an arrangement of external circuit connection terminals are proposed by the inventors (see JPA 2004-126551 and JPA H8-82804).
However, the inventors have found out that, in a case where various circuits disposed in such types of electro-optical devices are driven with a common power supply, deformation occurs in waveforms of signals due to the power supply. For example, the inventors have found out that, deformation occurs in waveforms of the sampling signals which are applied to the sampling circuit for sampling the image signals. More specifically, when transmission signals which are sequentially output from a shift register at a rising or falling time of the clock signal or the inverted clock signal are wave-shaped, deformation may occurs in waveforms of pulses of multiple-system enable signals which are used to output the sampling signals having a predetermined pulse width. If the deformation occurs in waveforms of the pulses of the enable signals, the waveform of the sample signals which are wave-shaped based on the transmission signals by using the enable signals to be output to the sampling circuit are deformed, so that display performance deteriorates. In addition to the sampling circuit, in a case where various circuits of the electro-optical device are driven with a common power supply, deformation occurs in the clock signals for driving the circuits.